Currently available non-rebreathing oxygen mash generally include the above-described face mask portion, oxygen reserve bag and intermediate oxygen entry port, with the oxygen reserve bag attached around, and extending away from, the distal end of the oxygen entry port. The oxygen reserve bag is typically constructed from a thin plastic material, and is configured in the shape of a bottle having a thin neck area, a wider main body, and a shoulder portion, having a gradually increasing width, joining the neck area and the main body of the oxygen reserve bag.
The face mask portion of a non-rebreathing oxygen mask is secured over the nose and mouth area of a patient using a head strap. When the face mask portion is suitably positioned, the main body of the oxygen reserve bag extends outwardly over the upper chest of the patient.
In normal operation, sufficient oxygen should be supplied to the oxygen reserve bag through the oxygen entry port to continuously inflate the oxygen reserve bag to at least two-thirds of its full volume. Unfortunately, as described in detail hereinbelow, this operational inflation requirement and the operational orientation of the oxygen reserve bag relative to a patient's chest, oftentimes result in a pinching off of the thin neck area of the oxygen reserve bag, deleteriously impeding the flow of oxygen to a patient.